Effects of season and time since defoliation on the nutritive characteristics of three irrigated perennial pasture species in northern Victoria 1. Energy, protein and fibre

1999 ◽  
Vol 39 (5) ◽  
pp. 555 ◽  
Author(s):  
C. R. Stockdale
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Crude Protein ◽  
Energy Content ◽  
Energy Concentration ◽  
Neutral Detergent Fibre ◽  
Plant Parts ◽  
Metabolisable Energy ◽  
Grazing Dairy Cows

The study reported here compared the nutritive characteristics of the 3 most common irrigated perennial pasture species grown in northern Victoria as they regrew after defoliation at various times during the year. In addition, the relative influence of changes to the proportions of morphological components and the nutritive characteristics of the individual components on the quality of whole plants was examined. The nutritive characteristics of white clover (Trifolium repens cv. Haifa), ryegrass (Lolium perenne cv. Ellet) and paspalum (Paspalum dilatatum) were examined at weekly intervals on 4 occasions during spring–autumn, 1993–94. On each occasion, pastures were defoliated with a drum mower and allowed to regrow for up to 9 weeks; defoliation dates were 24 September, 26 November, 28 January and 25 March. The variation in estimated metabolisable energy [obtained from in vitro dry matter (DM) digestibility], crude protein and detergent fibre concentrations within species was significantly (P<0.01) less than between clover and the grasses. White clover was consistently high in metabolisable energy (9.3–11.2 MJ/kg DM) and crude protein (17.7–27.7% DM), and low in neutral detergent fibre (27.8–39.8% DM) in all periods. At the other extreme, paspalum had a metabolisable energy content that peaked at 9.3 MJ/kg DM, and fell as low as 7.4 MJ/kg DM. Paspalum also had low protein (7.5–14.7% DM) and very high neutral detergent fibre (61.9–69.9% DM) concentrations. Ryegrass varied greatly in metabolisable energy concentration between the 4 periods, being high in autumn (average of 10.2 MJ/kg DM) and low in summer–autumn (average of 8.4 MJ/kg DM). Metabolisable energy apart, there were few differences in the crude protein and detergent fibre contents of ryegrass and paspalum. Perennial ryegrass is generally considered a superior feed to paspalum, but the data indicate this is not always the case under irrigation in northern Victoria. The nutritive characteristics of the plant fractions (leaf, stem, dead, inflorescence) were analysed separately to give an indication of the limits to selection by grazing cows. Differences in metabolisable energy between leaf and stem in both white clover and perennial ryegrass suggested that grazing dairy cows could consume a pasture diet which is likely to be slightly higher in energy than that in the herbage on offer. With paspalum, this is unlikely to be the case because differences in energy content between plant parts were small. However, with all species, cows should be able to consume herbage that is significantly higher in protein, and lower in detergent fibre, than that on offer because of differences in their concentrations in leaf and stem. The nutritive characteristics of morphological components of each species remained relatively constant throughout the study. Therefore, it would seem that it is the proportions of these fractions in the plant, together with severity of grazing, that will largely determine the degree of selection that can occur.

Effects of increasing the inclusion level of Atriplex amnicola in the diet of sheep

2009 ◽  
Vol 49 (11) ◽  
pp. 1029
Author(s):  
M. B. P. Kumara Mahipala ◽  
G. L. Krebs ◽  
P. McCafferty ◽  
K. Dods
Keyword(s):  
Crude Protein ◽  
Energy Content ◽  
Gas Production ◽  
Mineral Contents ◽  
Neutral Detergent Fibre ◽  
Freeze Dried ◽  
Acid Detergent Fibre ◽  
Inclusion Level ◽  
Metabolisable Energy

The effects of increasing the level of inclusion of fresh Atriplex amnicola Paul G.Wilson foliage in an oaten chaff (Avena sativa L.) diet fed to sheep were investigated. Six experimental diets were formulated to contain varying amounts [0, 161, 362, 496, 650 and 836 g/kg diet dry matter (DM)] of A. amnicola, and these diets were fed to individually penned sheep according to a Latin square design. Feed and faecal samples were analysed for crude protein, neutral detergent fibre, acid detergent fibre, acid detergent lignin, and ash contents. Mineral contents and 24 h in vitro gas production were measured in freeze-dried feed samples. As the level of inclusion of A. amnicola increased, digestibility of DM, organic matter and neutral detergent fibre increased (P < 0.05), reaching the peak at the 496 g/kg DM inclusion level and then decreasing (P < 0.05) thereafter. Acid detergent fibre digestibility followed a similar trend, but peak digestibility was at 362 g/kg DM inclusion level. Digestibility of crude protein continued to increase (P < 0.05) with increasing inclusion of A. amnicola. Gas production (24 h) from A. amnicola was lower (P < 0.05) than that from oaten chaff (24.4 v. 45.3 mL/200 mg DM) and also had lower metabolisable energy content (in vitro ME, 6.3 v. 8.6 MJ/kg DM). As the level of inclusion of A. amnicola in the diet increased, gas production and in vitro metabolisable energy content decreased (P < 0.05). The 496 g/kg DM inclusion level provided the optimum N : energy ratio for fermentation of dietary fibre. At this level of inclusion the diet was rich in Na, Ca, P, Mg, K, S, Mn and Zn. High inclusion levels improved the crude protein value of the diet but compromised fibre digestibility.

Effects of feeding additional pasture hay in autumn to dairy cows grazing irrigated perennial ryegrass-white clover pasture and supplemented with barley grain

2000 ◽  
Vol 40 (1) ◽  
pp. 1 ◽  
Author(s):  
W. J. Wales ◽  
D. W. Dellow ◽  
P. T. Doyle ◽  
A. R. Egan
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Milk Fat ◽  
Crude Protein ◽  
Barley Grain ◽  
Fibre Content ◽  
Neutral Detergent Fibre ◽  
Herbage Intake ◽  
Clover Pasture

Two experiments were undertaken to investigate responses by dairy cows grazing irrigated perennial pastures in autumn to supplementation with barley grain and pasture hay. Cows in late lactation were offered limited amounts of perennial ryegrass–white clover pasture at 26 kg DM/cow. day. Supplements were offered as nil or 6.0 kg DM/cow.day plus perennial pasture hay at 0, 0.5, 1.2, 2.0 or 3.0 kg DM/cow. day in a replicated experiment with 6 treatments using 36 cows (3 cows/treatment replication). The second experiment, which was conducted concurrently with experiment 1, measured aspects of rumen function and blood parameters in 3 groups of 3 rumen fistulated lactating cows grazing at the same herbage allowance and supplemented with barley (6.0 kg DM/cow. day) and 0, 1.0 or 3.0 kg DM of pasture hay daily. The in vitro DM digestibility and crude protein and neutral detergent fibre content of the barley and perennial pasture hay was 863 and 640 g/kg DM, 134 and 87 g/kg DM and 192 and 615 g/kg DM, respectively. In experiment 1, the cows from all treatments consumed herbage (mean s.d.) with an in vitro DM digestibility of 811 21.8 g/kg DM, crude protein content of 233 26.0 g/kg DM and neutral detergent fibre content of 404 39.4 g/kg DM compared with the pregrazed herbage on offer of 710, 152 and 526 g/kg DM, respectively. The mean pregrazing herbage mass of 3.75 t DM/ha in experiment 1 consisted of perennial ryegrass (580 g/kg DM), white clover (100 g/kg DM), weeds (110 g/kg DM) and dead material (210 g/kg DM). Without supplements, cows consumed 10.0 kg DM/day of this pasture with a neutral detergent fibre intake of 4.43 kg/day. The herbage grazed in experiment 2 was similar. Herbage intake did not decline to a large degree when barley was included in the diet indicating a very low substitution rate under the prevailing conditions where herbage allowance was only 26 kg DM/cow. day. Inclusion of hay progressively decreased (P<0.05) herbage intake, with substitution averaging 1.2 kg DM of herbage/kg DM of hay. Total DM intakes (15.5 kg DM/cow. day) were similar for the barley and the barley plus hay treatments up to 2.0 kg DM hay/cow. day; total DM intake was higher (P<0.05) for the 3.0 kg hay treatment. Milk production increased (P<0.05) with grain and hay supplementation, the marginal response being 0.8–1.0 kg milk/kg DM supplement, however, there was no significant difference between the 5 supplemented treatments. Supplementation with hay had no significant effect (P>0.05) on milk fat or milk protein contents which averaged 44.6 and 35.2 g/kg milk, respectively. The ratio of acetate + butyrate:propionate was 4.1:1 when cows consumed 6.0 kg barley, which was around the critical ratio of 4:1 for milk fat of 40 g/kg. Increasing the amount of hay in the diet did not alter this ratio. Because of the high levels of substitution of hay for pasture, changes in neutral detergent fibre intake were small between supplemented treatments. The rumen pH, ammonia-N concentration and volatile fatty acid concentration were relatively stable during the day because of a relatively slow rate of eating (1.5 kg DM/h) and long rumination time (about 6.8 h/day). Ruminal pH was rarely below 6.0, even when barley was given alone, suggesting that fibre digestion was not compromised. Additional fibre as supplemental hay to cows in late lactation grazing irrigated pasture did not improve milk production when the neutral detergent fibre content of the diet was above an average of 336 g/kg DM. Use of hay as a means of providing additional fibre could reduce herbage utilisation.

Nutritive value of corn silage in mixture with vine peas

2011 ◽  
Vol 51 (12) ◽  
pp. 1117 ◽  
Author(s):  
Y. Zhu ◽  
C. S. Bai ◽  
X. S. Guo ◽  
Y. L. Xue ◽  
Kazuo Ataku
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Nutritive Value ◽  
High Energy ◽  
Corn Silage ◽  
Energy Concentration ◽  
High Concentration ◽  
Neutral Detergent Fibre ◽  
Plastic Bags

Combining corn with legumes for silage is a feasible strategy to improve crude protein concentration in corn silage. This study was conducted to determine the fermentation characteristics and overall nutritive value of ensiled corn (Zea mays L.), vine peas (Pisum sativum L.), and mixtures of the two crops at three different ratios. The two crops were ensiled in corn/pea mixtures containing 0, 33, 50, 67, and 100% corn in vacuumed plastic bags for 60 days at room temperature. The addition of peas to corn crude protein and dry matter concentrations in the ensiled forages had a negligible influence on neutral detergent fibre concentration compared with corn silage. Corn silage had a greater (P < 0.05) lactic acid concentration than vine peas silage and the mixtures. There were no differences (P > 0.05) in in vitro dry matter and neutral detergent fibre digestibility among the silages made from the vine peas, corn, and mixtures. Improved fermentation characteristics were obtained in vine peas and corn mixture silage at a ratio of 33 : 67 compared with the other mixtures and vine peas silage. Results generated from this study suggest that combining vine peas with corn for silage could provide livestock with not only a high energy concentration feed, but a high concentration of crude protein as well.

Nitrogen fertiliser effects on nutritive characteristics of perennial ryegrass during late autumn, and mid- and late winter in western Victoria

2002 ◽  
Vol 42 (5) ◽  
pp. 541 ◽  
Author(s):  
J. L. Jacobs ◽  
F. R. McKenzie ◽  
G. A. Kearney
Keyword(s):  
Protein Content ◽  
Perennial Ryegrass ◽  
Crude Protein ◽  
Dry Matter ◽  
Water Soluble ◽  
Nitrate Content ◽  
Crude Protein Content ◽  
Nitrogen Fertiliser ◽  
Neutral Detergent Fibre ◽  
Metabolisable Energy

A study determined the effects of differing rates of nitrogen fertiliser [0 (N0), 25 (N1), 50 (N2) and 75�kg N/ha (N3)] during late autumn (T1) and mid- (T2) and late (T3) winter on the nutritive characteristics of perennial ryegrass over a 28-day period after each application. All nitrogen applications were made to pastures with a post-grazed residual mass (dry matter) of 1400 kg/ha. Changes in metabolisable energy followed similar patterns for all treatments within a given period. Metabolisable energy was highest in T1, ranging from 11.8 to 13.1 MJ/kg dry matter, followed by T2 (11.5-12.3 MJ/kg dry matter) and T3 (10.6-11.5 MJ/kg dry matter). Changes in crude protein for all treatments at each application time were similar, irrespective of rate of nitrogen application. At the commencement of treatment application times, the existing crude protein content (%DM) was highest in N3 (T1�19, T2 23, T3 22), followed by N2 (T1 18, T2 21, T3 21), N1 (T1 17, T2 20, T3 20) and N0 (T1 16, T2 17, T3 18). During both T1 and T2, neutral detergent fibre content decreased by 4 percentage units and increased by a similar amount during T3. Generally, neutral detergent fibre content (%DM) was highest during T3 (53-58%), followed by T2 (45-54%) and T1 (43-49%). Water-soluble carbohydrate content (%DM) increased during all treatment periods with the highest level observed during T1 (18-31%) followed by T2 (3-14%) and T3 (1-6%). Nitrate content (measured as nitrate-nitrogen) decreased throughout T1, primarily due to dry conditions, while during T2, levels for N3 and N2 were significantly (P<0.05) higher than for N1 and N0 following nitrogen fertiliser application. During T3, nitrate content increased for all treatments throughout the 28-day period, with highest nitrate levels being observed during T3. The effect of applied nitrogen on mineral content was variable within and across treatment periods. The study indicates that nitrogen fertiliser did not affect metabolisable (apart from N3 elevating metabolisable energy during T3), neutral detergent fibre or water-soluble carbohydrate contents of perennial ryegrass during the 28 days after nitrogen application, but increased crude protein content. Also, nitrogen fertiliser elevated nitrate content in perennial ryegrass. While the elevated nitrate content observed may result in subclinical effects, these levels are not considered fatal for dairy cows. Crude protein content was generally above 20% of dry matter throughout the study and close to 30% of dry matter for short periods during T2. Minimising the effect of excess nitrogen ingested by the grazing animal may require appropriate supplementation of low crude protein containing feeds such as cereal grains. It is argued that the effects of rain and temperature, which impact on soil nitrogen mineralisation, may have a greater influence on perennial ryegrass nitrate content than nitrogen fertiliser.

Dietary preferences of cows offered choices between white clover and 'high sugar' and 'typical' perennial ryegrass cultivars

2006 ◽  
Vol 46 (12) ◽  
pp. 1579 ◽  
Author(s):  
S. A. Francis ◽  
D. F. Chapman ◽  
P. T. Doyle ◽  
B. J. Leury
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Crude Protein ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Intake Rate ◽  
Neutral Detergent Fibre ◽  
Dietary Preferences ◽  
Structural Carbohydrate ◽  
Partial Preference

An experiment was conducted to compare dietary preferences of cows offered simple choices between spatially separated monocultures of perennial ryegrass cvv. AberDawn (AD) and AberElan (AE), and white clover (WC) under strip grazing. AberDawn was bred to express high water soluble carbohydrate concentrations, whereas AE has typical levels. The proposed hypotheses were that cows would exhibit a partial preference for the ryegrass cultivar with a higher concentration of non-structural carbohydrates, and that there would be an interaction between the non-structural carbohydrate concentration of the ryegrass and strength of preference for WC. Non-lactating cows were offered a pasture allowance of about 20 kg DM each day for 9 days in 3 ‘choice’ treatments: AD + WC, AE + WC and AD + AE. All pastures had similar estimated metabolisable energy contents, but AD had a higher crude protein (136 v. 118 g/kg DM) and slightly lower neutral detergent fibre (480 v. 497 g/kg DM) concentration than AE, and non-structural carbohydrate concentrations were similar in both grasses. White clover had higher crude protein (236 v. 127 g/kg DM), and lower neutral detergent fibre (317 v. 489 g/kg DM) and non-structural carbohydrate concentrations (140 v. 183 g/kg DM), and contained less dead material (60 v. 242 g/kg DM) than the grasses. AberDawn contained less (P<0.05; 578 v. 698 g/kg DM) green ryegrass than AE. Pre-grazing pasture mass (1870 v. 2010 kg DM/ha), pasture allowance (23 v. 25 kg DM/cow), and residual pasture mass (1610 v. 1710 kg DM/ha) were lower for AD than AE, and for WC were lower (P<0.05) than for both grasses. Dry matter intake, intake rate and bite size were lower (P<0.05) on AD + AE than on treatments containing WC. Cows grazing AD + AE ruminated longer (P<0.05), ruminated more (P<0.05) boli, and had more (P<0.05) ruminating chews than those on treatments including WC. The cows on AD + AE had more (P<0.05) total chews than those on AD + WC or AE + WC, but grazing time was not always significantly different between choice treatments. It is suggested that the longer ruminating times and greater number of boli processed in cows grazing only grass may reflect the slower digestion rates of ryegrass compared with clover. Cows grazing the AD + WC or AE + WC choice treatments showed a partial preference for WC, spending more (P<0.001) time grazing and consuming more (P<0.001) WC than ryegrass. Within the AD + AE choice treatment, cows spent more (P<0.05) time grazing and consumed more (P<0.05) AE than AD. Using the mean of 2 methods of estimation, the partial preferences for AD + WC, AE + WC and AD + AE were 39 : 61, 41 : 59 and 45 : 55, respectively.

Effect of grain supplementation and the provision of chemical or physical fibre on marginal milk production responses of cows grazing perennial ryegrass pastures

2001 ◽  
Vol 41 (4) ◽  
pp. 465 ◽  
Author(s):  
W. J. Wales ◽  
Y. J. Williams ◽  
P. T. Doyle
Keyword(s):  
Milk Production ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Milk Fat ◽  
Crude Protein ◽  
Ground Level ◽  
Large Degree ◽  
Herbage Intake ◽  
Cereal Grain

An experiment was undertaken to establish the marginal milk production response from cereal grain supplementation by dairy cows grazing irrigated perennial pastures in spring and whether the addition of a hay supplement would improve that response. Cows were offered perennial ryegrass (Lolium perenne L.)–white clover (Trifolium repensL.) pasture at allowances (measured to ground level) of 20 or 40 kg dry matter (DM)/cow.day. Additional cows offered the low allowance were also offered supplements of pasture hay as a cube or pellet (2.5 kg DM/day), cereal grain as a pellet (5.0 kg DM/day) or cereal grain plus pasture hay (7.5 kg DM/day) as a pellet (1.75:1 DM basis) or cube (1.97:1 DM basis). The 7 treatments were replicated 3 times, and 63 cows were used (3 cows/treatment). The in vitro DM digestibility, crude protein and neutral detergent fibre (NDF) concentration of the barley and perennial pasture hay were 863 and 563 g/kg DM, 131 and 92 g/kg DM, and 182 and 666 g/kg DM, respectively. Cows from all treatments consumed herbage with an in vitro DM digestibility of 833 g/kg DM, crude protein content of 214 g/kg DM and NDF concentration of 457 g/kg DM compared with the pregrazed herbage on offer of 771, 174 and 527 g/kg DM, respectively. The mean pregrazing herbage mass of 4.13 t DM/ha consisted of perennial ryegrass (507 g/kg DM), white clover (188 g/kg DM), weeds (194 g/kg DM) and dead material (111 g/kg DM). Without supplements, cows consumed 11.2 kg DM/day at the low pasture allowance and 15.6 kg DM/day at the high allowance. Herbage intake did not decline to a large degree when barley was included in the diet, where a substitution rate of 0.2 kg reduction in pasture DM/kg DM cereal grain supplement was measured. The NDF concentration of the diet consumed was lowest (P< 0.05) for the grain pellet treatment (370 g NDF/kg DM) and highest (P&lt;0.05) for the fibre pellet (493 g NDF/kg DM) and the fibre cube (507 g NDF/kg DM) treatments. Fat-corrected milk yield increased (P<0.05)) from 20.1 to 24.5 kg/cow.day when cows consumed 4.5 kg DM cereal grain/day with a marginal milk response of 1.0 kg 4% fat-corrected milk/kg DM concentrate supplement. Supplementation with grain or hay had no significant effect (P>0.05) on milk fat, protein or lactose concentrations. The cows offered the high allowance spent more (P<0.05) time grazing than those offered the low allowance, but there were no significant differences in rumination time. Cows spent more time ruminating when consuming the grain &plus; fibre cube compared with the other supplement treatments, which were lower (P<0.05) and similar. Cows offered pasture at the low allowance ruminated the least. The rumen pH was not different between treatments and averaged 5.9. The ratio of acetate plus butyrate: propionate was not different between treatments and averaged 4.3. This study has shown that feeding cereal grain to cows grazing pastures high in perennial ryegrass resulted in acceptable marginal milk responses of 1 kg milk/kg DM of cereal grain in spring because of sufficient NDF in the diet. As there was adequate NDF in the diet, further supplements with pasture hay as cubes or pellets had no effect on marginal milk responses .

Supplementation of grazing dairy cows with a brewers grains/treated straw mixture

1990 ◽  
Vol 1990 ◽  
pp. 46-46 ◽  
Author(s):  
J.D. Leaver ◽  
R.C. Campling
Keyword(s):  
Dairy Cows ◽  
Crude Protein ◽  
Dry Matter ◽  
Barley Straw ◽  
Severe Drought ◽  
Grass Silage ◽  
Metabolisable Energy ◽  
Grazing Dairy Cows ◽  
Similar Cost ◽  
Friesian Cows

Supplementary feeding of grazing dairy cows is often uneconomic, and whilst supplementation with silage (buffer feeding) can be worthwhile, this often leads to a depletion of winter forage stores. In this study, a mixture of brewers grains and treated straw was used as a supplement. Offered as a 1:1 mixture in the dry matter (DM), it is a purchased substitute for grass silage, having a similar cost, and similar metabolisable energy (ME) and crude protein (CP) contents. The high seasonality adjustments to milk price in mid-late season make supplementation potentially worthwhile.Experiments were carried out from April to September in 1988 and 1989, which had moderate and very low rainfall respectively. Each year 20 British Friesian cows which calved December to March (1988 experiment) and February-April (1989) were allocated at random to either treatment B or C. In B, the cows were offered a 1:1 mixture (DM basis) of brewers grains and NaOH treated chopped barley straw for 60 minutes after morning milking. In C, the cows received no supplement. Both groups were fed 1.0 kg/day of concentrates in the milking parlour. Due to the severe drought in 1989, concentrate feeding was increased to 5.0 kg/day for all cows during the last 4 weeks of the experiment. Also, urea-treated whole crop wheat was fed at a level of 2.5 kg DM/day during the last 7 days.

The assessment of herbage legume varieties. II. In vitro digestibility, water soluble carbohydrate, crude protein and mineral content of primary growth of clover and lucerne

1966 ◽  
Vol 66 (3) ◽  
pp. 351-357 ◽  
Author(s):  
W. Ellis Davies ◽  
G. ap Griffith ◽  
A. Ellington
Keyword(s):  
White Clover ◽  
Crude Protein ◽  
Dry Matter ◽  
Red Clover ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
In Vitro Digestibility ◽  
Primary Growth

The primary growth of eight varieties of three species–white clover (3), red clover (4) and lucerne (1)–was sampled at fortnightly intervals and the percentage dry matter, in vitro digestibility, crude protein, water soluble carbohydrates, P, Ca, K, Na and Mg were determined.Differences between species were nearly always significant and the general order of merit was white clover, red clover and lucerne. The exceptions were for dry-matter percentage where this order was reversed, and red clover had the lowest Na and highest Mg content.

Effects of feeding ryegrass of varying maturity on the metabolism and composition of lipids in the rumen of sheep

1986 ◽  
Vol 106 (3) ◽  
pp. 445-448 ◽  
Author(s):  
T. Gerson ◽  
A. John ◽  
A. S. D. King
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Linoleic Acid ◽  
Blood Plasma ◽  
Polyunsaturated Fatty Acid ◽  
Perennial Ryegrass ◽  
Crude Protein ◽  
Linseed Oil ◽  
Triacyl Glycerol

SummaryTwo experiments were carried out to test the effects of ryegrass maturity on rumen lipid metabolism. In the first experiment the effect of stage of maturity of perennial ryegrass on lipid metabolism in the rumen was studied with grazing sheep fitted with rumen cannulae. The pasture was either immature (13·8% crude protein), mature (8·1% crude protein) or senescent (5·5% crude protein).The ratesin vitroof triacyl glycerol lipolysis and linoleic acid (18: 2w6) hydrogenation were found to decrease with increasing age of the ryegrass.In the second experiment the sheep were dosed with emulsified linseed oil (30 g) via rumen cannulae while grazing immature or senescent ryegrass and the rumen digesta and blood plasma sampled at 0, 4 and 8 h after dosing.The proportions of linseed oil retained in the rumen were greater and blood plasma linoleic (18:2w6) and linolenic (18:3w3) acid concentrations higher when senescent ryegrass was fed.It was concluded that the rates of rumen lipolysis and hydrogenation decreased with the age of pasture and that after dosing with linseed oil the polyunsaturated fatty acid concentrations in blood plasma increased.

scholarly journals The effect of dairyshed effluent irrigation on the occurrence of plant pathogenic Pythium species in pasture

2000 ◽  
Vol 53 ◽  
pp. 436-440 ◽  
Author(s):  
N.W. Waipara ◽  
S.K. Hawkins
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Subterranean Clover ◽  
Preliminary Survey ◽  
Pythium Species ◽  
Effluent Irrigation ◽  
Pathogenicity Tests ◽  
Roots In Vitro

A preliminary survey of pastures sprayirrigated with dairyshed effluent revealed a significant increase in the population of plant pathogenic Pythium species isolated from both soil and roots In vitro pathogenicity tests showed the majority of these isolates to be pathogenic when inoculated onto the seedlings of white clover subterranean clover and perennial ryegrass although both clover species were more susceptible to Pythiuminduced disease than ryegrass

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